Securing means for orthodontic appliance

ABSTRACT

A manually retractable locking means is provided on the end of the inner arch of an orthodontic appliance, which engages the buccal tube in which the end of the arch resides, thereby to prevent undesired or accidental removal of the arch from the buccal tube. In similar vein the face bow, to which the inner arch is secured, is provided with a stop means associated with the resilient retractive elastic customarily used with the face bow, which prevents the face bow from being completely separated from the neck strap or retaining head gear to which it is secured. In this way a double safety feature is provided to prevent harm to the wearer by the accidental pulling out and snapping back of the face bow and/or the inner arch.

United States Patent [191 Snead [4 1 Sept. 9, 1975 SECURING MEANS FORORTHODONTIC APPLIANCE [75] Inventor: Wilford A. Snead, West Covina,

Calif.

[73] Assignee: Ormco Corporation, Glendora,

Calif.

[22] Filed: Feb. 13, 1974 [21] Appl. No.: 442,281

3,686,757 8/1972 Mcvickersu 32/140 Primary Examiner-Robert PeshockAttorney, Agent, or Firm-Jessup & Beecher [5 7] ABSTRACT A manuallyretractable locking means is provided on the end of the inner arch of anorthodontic appliance, which engages the buccal tube in which the end ofthe arch resides, thereby to prevent undesired or accidental removal ofthe arch from the buccal tube. In similar vein the face bow, to whichthe inner arch is secured, is provided with a stop means associated withthe resilient retractive elastic customarily used with the face bow,which prevents the face bow from being completely separated from theneck strap or retaining head gear to which it is secured. In this way adouble safety feature is provided to prevent harm to the wearer by theaccidental pulling out and snapping back of the face bow and/or theinner arch.

10 Claims, 15 Drawing Figures PA I EHTEU 9195 3803.604

SHEET 2 U? 3 Fig. 6.

PMSHEU 9975 3,903,604

SHKET 3 of 3 SECURING MEANS FOR ORTHODONTIC APPLIANCE BACKGROUND OF THEINVENTION In a typical orthodontic installation which requires aconstant retractive force applied to teeth through buccal tubes, aninner arch is provided, the ends of which ride in a respective buccaltube inside the wearers mouth. Stop members on the arch apply a rearwardor retractive force to the tooth. This rearward force is derived from aface bow which is secured to the inner arch and extends across the faceof the wearer and to the rear, where it is resiliently secured to a neckstrap or other retaining head gear which runs around the back of thehead or neck. The resilience of the connecting link betweeen the facebow and the neck strap at each side provides a relatively constant forcewhich biases the inner arch to the rear and hence applies a rearwardretractive force to the teeth involved.

It has been found that there is some danger in this structure in thatthe face bow may be pulled forward against the resilience of thetensioning member, either accidentally or malicously. This pulls theends of the inner arch out of the buccal tubes and leaves them facingtowards the wearers face under the tension of the elastics at each sidean extremely dangerous condition. When the pulling force is removed, asfor example if a malicious person pulls out and lets go, the two ends ofthe arch stab to the rear and may inflict'critical and permanent injury,as for example by putting out an eye.

At times the orthodontist meets this problem, plus the other vexingproblem of having a juvenile wearer simply remove the application andrefuse to wear it by tieing the face bow in place using stainless steelwire. This, however, has a number of disadvantages, one of which ishygenic. If the bow is tied in place for approximately six weeks atypical time between appointments the patient will have a difficult timebrushing his teeth, since the design of the typical inner arch is suchthat it covers most of the upper teeth, thereby making it difficult forproper brushing. Secondly, the continuous wearing of the appliance forsuch a long period gives the wearer no option which might otherwise bepermitted by the orthodontist, as for example a willingness to wear theface bow during the day if it could be taken off at night, or viceversa. Another disadvantage is that the neck pad or retaining head gearbecomes quite dirty, since there is no opportunity to clean the hair orthe back of the neck.

SUMMARY OF THE INVENTION The present invention solves the problemmentioned above by providing a lock at the buccal tube which preventsthe inner arch from accidental removal therefrom and also by providing alimit stop in connection with the resilient connection between the facebow and the neck strap, which limits the amount by which the face bowcan be pulled forward. Thus there is no danger that the appliance can bepulled so far away from the wearers face as to constitute a serioushazard when it snaps back. In each case, however, the stop means isoperable by the wearer, if he wants to go to the deliberate effort ofactuating it, so that the appliance can without undo difficulty beremoved for cleaning the teeth and the head and neck area.

DESCRIPTION OF THE DRAWINGS In accordance with this invention severalforms thereof will now be described in connection with the accompanyingdrawings wherein:

FIG. 1 is a plan view of the orthodontic device looking down upon thehead of the wearer, which is shown in phantom;

FIG. 2 is a rear view along line 22 in FIG. 1;

FIG. 3 is a fragmentary enlarged view of one form of locking means forpreventing undesired removal of the inner arch from the buccal tube onthe tooth;

FIG. 4 is a cross-section taken on line 44 in FIG.

FIG. 5 is an enlarged fragmentary section similar to FIG. 4 showing theparts in a different relative position;

FIG. 6 is a view similar to FIG. 3 showing an alternative form oflocking means;

FIG. 7 is a sectional view taken on line 77 in FIG.

FIG. 8 is an enlarged section similar to FIG. 7 showing the parts inanother relative position;

FIG. 9 is a fragmentary view showing one form of tensioning link ormechanism for the orthodontic face bow and including the safety featureof a stop means which limits the extensibility of the tensioning meansor rubber band;

FIG. 10 is a view taken on line 10-10 in FIG. 9;

FIG. 11 is a view similar to FIG. 9 showing the parts in anotherrelative position, this being the position of maximum extensibility;

FIG. 12 shows another form of tensioning mechanism with associated stopmeans;

FIG. 13 is a view taken on line l3l3 in FIG. 12 and also represents aview which would be seen from line 13l3 in FIG. 1;

FIG. 14 shows a third form of tensioning mechanism and stop means; and

FIG. 15 is a view taken on'line 15-l5 in FIG. 14.

DETAILED DESCRIPTION OF THE EMBODIMENT OF THE INVENTION Referring to thedrawing; 20 represents an inner arch, the ends of which are adapted toextend rearwardly into the wearers mouth and to be engaged with buccaltubes on a pair of teeth 22 to which an orthodontic retractive force isto be steadily applied. The inner arch has secured thereto a face bow 24extending across the faceof the wearer and rearwardly into resilientengagement with a neck strap 26 which extends around the back of theneck of the wearer. At each side of the head 28 of the wearer is anelongate tension member, shown here as a rubber band 30 forming aresilient tenison connection between the face bow 24 and the neck strap26, and thereby applying a steady retractive rearward force to the innerarch 20 and hence to the teeth 22. p

The force on the teeth 22 is applied from the inner arch 20 by way of atooth band 32 to which is affixed a buccal tube 34. The end of the innerarch 20 extends through the tube 34 and brings a stop member 36 on thearch 20 into engagement with the front facing end of the tube 34,thereby transferring the force from the rubber band 30 to the tube 34and hence to the tooth 22. The customary neck pad 38 is secured to theneck strap 26 adjacent the neck of the wearer 28 to provide a softerbearing surface.

Referring to FIG. 3, the end of the arch will be seen extending throughthe buccal tube 34 with the stop means 36 bearing against the tube toapply the rearward retractive force. In accordance with the presentinvention, a groove 40 is provided in the end of the inner arch 20 thatresides within the buccal tube 34. A transverse slot 42 is provided inthe tube 34 and riding in the slot is a transverse pin 44 biasedinwardly into the groove 40 by a leaf spring 46 secured to the exteriorof the tube 34 and having an inward corrugation 48 that bears againstthe pin 44. The pin 44 is thus resiliently detented into the groove 40in the arch 20, providing a manually actuable locking means whichprevents or inhibits the arch 20 from being withdrawn from the tube 34except when the leaf spring 46 is deliberately lifted out, freeing thepin 44 from the groove 40. The pin 44 is maintained laterally in placeby enlargements 50 on each end thereof which prevent it from slidinglaterally out of the groove 40.

To simplify insertion of the arch 20 into the tube 34, the former isbevelled at the end as shown at 52 in FIG. 5. Thus it is merelynecessary to insert the end of the arch 20 into the tube 34 until thebevel 52 engages the pin 44. Continued inward force will cam the pin 44outwardly against the force of the spring 46, as shown in FIG. 5, untilthe end of the arch 20 has reached the position shown in FIG. 4,whereupon the pin 44 moves automatically into place in the groove 40under the bias of the spring 46. Thereafter it is necessary to manuallylift the spring 46 away from the tube 34 in order to remove the arch 20from the mouth.

An alternate form oflocking mechanism is illustrated in FIGS. 6-8. Herethe arch 20a is provided at its extreme end with a longitudinal slot 54within which is pivoted a pair of locking pawls 56 on respective pivotpins 58 spanning the slot 54. A single compressiion spring 60 biases theends of each pawl 56 outwardly, the biasing action being halted by theengagement of the opposite ends of the pawls, as shown at 62. In thisoutwardly biased position, as best seen in FIG. 7, the pawls 56 are inposition to engage the rear end 64 of the buccal tube 34a, and therebyprevent withdrawal of the arch 20a from the tube. 34a.

The pawls 56 may be deliberately pushed inward so as to clear the end 64of the tube, whereupon the arch 20a may be withdrawn, as shown in FIG.8. FIG. 8 also illustrates the position of the parts as the arch isbeing inserted into the buccal tube 34a. The sloping angle at the outersurface of pawls 56 allows them to be cammed inwardly to the positionshown in FIG. 8 as the arch 20a is pushed into the buccal tube 34; butas noted retraction of the arch is prevented once the pawls 56 snapoutwardly into the position shown in FIG. 7.

In FIGS. 9-11 there is illustrated one form of safe tensioning mechanismby which the face bow 24a may be linked to the neck strap 26a.

The link consists of a first member and a second member slidcablymounted with respect to each other. The first member in the case of FIG.9 consists of a sleeve 66 bonded as by solder to a linkage rod 68 andconnected through an adjustment or omega loop 70 to the neck strap 26avia a hook 72. This first member thus forms in effect a part of the endportion of the neck strap 26a. The second member in this instance isconstituted by the end of the face bow 26a, which passes through andreciprocates within the sleeve 66. The left-hand end of the linkage rod68 has a hook 74,

and the face bow 24a has another hook 76 thereon spaced a short distanceforwardly of where the face bow 24a passes into sleeve 66. Linkagebetween the hooks 74 and 76 is provided by an elongate tension member30a in the form of a rubber band as shown in FIG. 10. In order to limitthe extensibility of the rubber band 301: and to prevent completewithdrawal of the face bow 24a from the sleeve 66, pin 78 is passedthrough the extreme end of the face bow 24a. The right-hand end of thesleeve 66 and the pin 78 thus constitute stop means engageable with eachother to limit the extensibility of the rubber band 30a, as shown inFIG. 11. Alternatively the stop at 78 may be made by applying aprotrusion of solder or by swaging the rod outward.

While the linkage rod 68 may, if desired, be directly hooked to the hook72, it is preferred to provide an intermediate adjustment or omega loop70, which may be manually adjusted by the orthodontist with a pair ofpli ers to set the initial tension in the rubber band 30a. Thus the loopshould be closed sufficiently to effect the proper tension in the rubberband 30a, while still maintaining a working clearance between the sleeve66 and the stop in 78. The linkage may be deliberately disengaged, ifdesired, by retracting the omega loop 70 to the rear and then lifting itoff from the hook 72.

A second form of safety tensioning mechanism is shown in FIGS. 12 and13. In this embodiment the first member consists essentially of the hook74a which extends through a slot 80 formed in an elongate linkage orslide plate 82, the other end of which is coupled by means of a hole 84to the end of the face bow 24. Secured to the plate 82 adjacent thelinkage hole 84 is a hook 76a, and tensioned between the hooks 74a and76a is the rubber band 30.

In this embodiment the adjustment loop 70 is not employed, but insteadthe desired tension in the rubber band 30 is achieved at the back of theneck by adjusting the neck strap 26, as shown at 86 in FIG. 2.

The working span for the linkage is typically about 0.125 inch, and thisis achieved in the embodiment shown in FIGS. 12 and 13 by making theslot 80 0.125 inch long. The initial adjustment of the apparatus is suchas to position the hook 74a at the right-hand end of slot 80, as shownin FIGS. 12 and 13.

It will be readily evident that in this embodiment the stop means isconstituted by the hook 74a on the first member which is engageable withthe right-hand end of the slot 80 on the second member to limit theextensibility of the rubber band 30.

The embodiment shown in FIGS. 12 and 13 has the advantage that thewearer himself, or a companion, if he needs help, may readily completelydisengage the face bow from the neck strap by removing the rubber band30 from the hook 74a and then lifting the elongate slide plate 82 awayfrom the neck strap 26.

A third variant of the face bow tensioning mechanism is shown in FIGS.14 and 15, which constitute in some respects a modification of the formshown in FIGS. 9-11. Here the first member includes a tube or sleeve 66bsecured as by soldering through the intermediacy of a spacing disk 90,to the neck strap 26!). Extended through and i'eciprocable in the sleeve66b is a slider rod 92, to the forward end of which is secured alaterally extending hook 7619, that reciprocates back and forth in alongitudinal notch or slot 94 formed in the forward end of the tube 66b.

The face bow 24b is linked to the hook 76b through the intermediacy ofan adjustment or omega loop 70b. Tensioned between the hook 76b.andahook 74b secured to the rearward end of the sleeve 66b is the rubberband 30b forming the retractive force for the apparatus. In this casethe stop means is provided by an enlarged or swaged end 78a on the sliderod 92, which en-J gages the rearward end of the sleeve 66b to limit theextensibility of the rubber band 30b. As in the case of the modificationshown in FIGS. 12 and 13, the linkage may be deliberately disengagedsimply by removing the rubber band 30b from the hooks 74b and 76b andthen lifting the omega loop 70b off the hook 76b.

It will be noted that the embodiments of the invention shown in FIGS.12, 13, 14 and 15 have the feature that the linkage at the rear of theface bow can be disengaged only by deliberately removing the tensionedrubber band b from at least the hook 76b (FIG. 15). The band 30b thushas the second function of insuring against disengagement of the facebow from the neck strap.

FIG. 1 shows safety devices at both the side of the head (at 30) and atthe buccal tube 34, and at times it may be well to employ such at bothpositions. However, generally the safety features of the presentinvention will be needed only at one position or the other.

What is claimed is: l. Orthodontic appliance comprising: an inner arch;a face bow secured to said inner arch; each end of said arch beingadapted to extend through a respective buccal tube secured to a tooth,and having stop means bearing against said tooth to apply a retractiveforce to the tooth;

manually actuable locking means forming an interengagement between eachsaid end and its respective tube for preventing undesired removal ofsaid arch from said tube;

a first member and a second member slideably mounted with respect toeach other;

said first member being adapted to being secured to the end of a neckstrap or retaining head gear; said second member forming at least a partof the end portion of said face bow;

a first hook extending laterally from said first member;

a second hook extending laterally from said second member;

an elongate tension member tensioned between said hoods; and

stop means on said first and second members respectively, and engageablewith each other to limit the extensibility of said tension member and toprevent undesired separation of said first and second members.

2. Orthodontic appliance comprising:

a buccal tube adapted to be secured to a tooth;

an inner arch having an end extended through said tube and having stopmeans bearing against said tube to apply a retractive force to thetooth; characterized by manually actuable locking means forming aninterengagement between said end and said tube for preventing undesiredremoval of said end from said tube.

3. Appliance in accordance with claim 2 wherein said locking meanscomprises:

- a groove in said arch; detent means mounted on said tube andresiliently biased into said groove. 4. Appliance in accordance withclaim'3 whereinsaid detent means comprises:

a pin residing in a slot in' said tube; and a leaf spring secured tosaid tube and bearing inwardly against said pin. 5. Appliance inaccordance with claim 2 wherein said locking means comprises:

pawl means pivotally mounted to said arch end and engageable with theend of said tube; I I spring means for biasing said pawl means intoposition to engage said tube end; thereby to prevent removal of saidarch from said tube except when said pawl means are deliberatelyretracted against the bias of said spring means. 6. Tensioning mechanismfor an orthodontic face bow comprising:

a first and a second member slideably mounted with respect to eachother; said first member forming at least a part of the end portion of aretaining head gear or neck strap; said second member forming at least apart of the end portion of a face bow; a first hook extending laterallyfrom said first member; a second hook extending laterally from saidsecond member; an enlongate tension member tensioned betweeen saidhooks; and stop means on said first and second members respectively andengageable with each other to limit the extensibility of said tensionmember and to prevent undesired separation of said first and secondmembers. 7. Tension mechanism in accordance with claim 6 wherein saidtension member comprises an elastic band.

8. Tensioning mechanism adapted to link a first element comprising aface bow, to a second element comprising the end portion of a retaininghead gear or neck strap, said mechanism comprising:

a first and a second member slideably mounted with respect to eachother;

said first member being joined to one of said elements;

said second member comprising an elongate plate having a longitudinalslot, and attachment means adjacent one end for attachment to the otherof said elements;

a first hook extending laterally from said first member through saidslot;

a second hook extending laterally from said elongate plate adjacent saidattachment means;

an elongate tension member tensioned between said hooks;

said first hook and an end of said slot constituting stop meansengageable with each other to limit the extensibility of said tensionmember and to prevent undesired separation of said first and secondmembers.

9. Tensioning mechanism for an orthodontic face bow comprising:

a first and second member slideably mounted with respect to each other;

said first member comprising a sleeve and linkage rod secured thereto,and means for connecting said rod to the neck strap;

said second member comprising an end of the face bow extending throughsaid sleeve;

a first hook extending laterally from said first membet;

a second hook extending laterally from said second member;

an elongate tension member tensioned between said hooks;

a lateral extension at the end of said face bow en gageable with the endof said sleeve and serving as a stop means to limit the extensibility ofsaid extension member and to prevent undesired separation of said firstand second members.

10. Tensioning mechanism for an orthodontic face bow comprising:

a first and a second member slideably mounted with respect to eachother;

said first member comprising a sleeve secured to the end of the neckstrap and having a longitudinal notch opening toward the face bow; saidsecond member comprising a rod slideable in separation of said first andsecond members.

1. Orthodontic appliance comprising: an inner arch; a face bow securedto said inner arch; each end of said arch being adapted to extendthrough a respective buccal tube secured to a tooth, and having stopmeans bearing against said tooth to apply a retractive force to thetooth; manually actuable locking means forming an interengagementbetween each said end and its respective tube for preventing undesiredremoval of said arch from said tube; a first member and a second memberslideably mounted with respect to each other; said first member beingadapted to being secured to the end of a neck strap or retaining headgear; said second member forming at least a part of the end portion ofsaid face bow; a first hook extending laterally from said first member;a second hook extending laterally from said second member; an elongatetension member tensioned between said hoods; and stop means on saidfirst and second members respectively, and engageable with each other tolimit the extensibility of said tension member and to prevent undesiredseparation of said first and second members.
 2. Orthodontic appliancecomprising: a buccal tube adapted to be secured to a tooth; an innerarch having an end extended through said tube and having stop meansbearing against said tube to apply a retractive force to the tooth;characterized by manually actuable locking means forming aninterengagement between said end and said tube for preventing undesiredremoval of said end from said tube.
 3. Appliance in accordance withclaim 2 wherein said locking means comprises: a groove in said arch;detent means mounted on said tube and resiliently biased into saidgroove.
 4. Appliance in accordance with claim 3 wherein said detentmeans comprises: a pin residing in a slot in said tube; and a leafspring secured to said tube and bearing inwardly against said pin. 5.Appliance in accordance with claim 2 wherein said locking meanscomprises: pawl means pivotally mounted to said arch end and engageablewith the end of said tube; spring means for biasing said pawl means intoposition to engage said tube end; thereby to prevent removal of saidarch from said tube except when said pawl means are deliberatelyretracted against the bias of said spring means.
 6. Tensioning mechanismfor an orthodontic face bow comprising: a first and a second memberslideably mounted with respect to each other; said first member formingat least a part of the end portion of a retaining head gear or neckstrap; said second member forming at least a part of the end portion ofa face bow; a first hook extending laterally from said first member; asecond hook extending laterally from said second member; an enlongatetension member tensioned betweeen said hooks; and stop means on saidfirst and second members respectively and engageable with each other tolimit the extensibility of said tension member and to prevent undesiredseparation of said first and second members.
 7. Tension mechanism inaccordance with claim 6 wherein said tension member comprises an elasticband.
 8. Tensioning mechanism adapted to link a first element comprisinga face bow, to a second element comprising the end portion of aretaining head gear or neck strap, said mechanism comprising: a firstand a second member slideably mounted with respect to each other; saidfirst member being joined to one of said elements; said second membercomprising an elongate plate having a longitudinal slot, and attachmentmeans adjacent one end for attachment to the other of said elements; afirst hook extending laterally from said first member through said slot;a second hook extending laterally from said elongate plate adjacent saidattachment means; an elongate tension member tensioned between saiDhooks; said first hook and an end of said slot constituting stop meansengageable with each other to limit the extensibility of said tensionmember and to prevent undesired separation of said first and secondmembers.
 9. Tensioning mechanism for an orthodontic face bow comprising:a first and second member slideably mounted with respect to each other;said first member comprising a sleeve and linkage rod secured thereto,and means for connecting said rod to the neck strap; said second membercomprising an end of the face bow extending through said sleeve; a firsthook extending laterally from said first member; a second hook extendinglaterally from said second member; an elongate tension member tensionedbetween said hooks; a lateral extension at the end of said face bowengageable with the end of said sleeve and serving as a stop means tolimit the extensibility of said extension member and to preventundesired separation of said first and second members.
 10. Tensioningmechanism for an orthodontic face bow comprising: a first and a secondmember slideably mounted with respect to each other; said first membercomprising a sleeve secured to the end of the neck strap and having alongitudinal notch opening toward the face bow; said second membercomprising a rod slideable in said sleeve, and means for connecting saidrod to the face bow; a first hook extending laterally from said sleeveat the end of said sleeve opposite said notch; a second hook extendinglaterally from said rod and positioned to slide back and forth in saidnotch; a lateral extension on the end of said rod engageable with theend of said sleeve to limit the extensibility of said tension member andto prevent undesired separation of said first and second members.